Welding machine



July 11, 1950 J. R. wlRT ET AL 2,515,106

WELDING MACHINE Filed May 21, 1948 '7 Sheets-Sheet l July 11, 1950 J. R. wlRT ETAL 2,515,105

WELDING MACHINE Filed May 21, 1948 '7 Sheets-Sheet 2 MN w I INVENTORS wY/wf/M @www I July 1l, 1950 J.R.w1RT ETAL WELDING MACHINE '7 Sheets-Sheet 3 Filed May 21, 1948 JNVENToRs July 1l, 1950 J. R. wiT ETAL WELDING MACHINE 7 Sheets-Sheen'l 4 Filed May 21, 1948 SQ 1n.| i i l l l 1| July 11, 1950 J. wlRT ET AL WELDING MACHINE 7 Sheets-Sheet 5 Filed May 2l, 1948 :VIII

July l1, 1950 J. R. wiRT ETAL 2,515,106

I WELDING MACHINE Filed May 21, 1948 7 Sheets-Sheet 6 k? ll 126 July 11, 1956 J. R. wxRT ET AL WELDING MACHINE '7 Shees-Sheet 7 Filed May 21, 11.9%`

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BY ,1, MMM/.152

Patented July 11, 1955@ UNITED STATES PATENT OFFICE WELDING MACHINE Application May 21, 1948, Serial No. 28,366

15 Claims.

This invention relates to the manufacture of horns for automotive vehicles, more particularly the type of horn disclosed in the copending apu plication of White and Brundage, Serial No. 80,- 854, led March 1l, 1949. In the manufacture of this horn the pole piece assembly is welded to the horn base while a predetermined gap is maintained between the armature and the pole pieces by a shim located between the armature and the pole pieces while the magnet coil is energized so that the armature will press against the shim and the shim against the pole pieces while welding takes place.

An object of the invention is to provide an apparatus by which the welding of the pole piece or magnet core to the frame takes place while current is applied to the magnet coil.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Figs. 1 and 2 are front and side views respectively of the apparatus embodying the present invention;

Figs. 3 and 4 together constitute a plan View of portion of the apparatus, this view being on line 3--3 of Fig. 1;

Fig. 5 is a fragmentary sectional view on the line 5-5 of Fig. 3;

6 is a View in the direction of arrow 6 of Fig. 5;

Fig. 7 is a fragmentary sectional View on the line 'i'-'I of Fig. 3;

Fig. 8 is a fragmentary sectional view on the line 8 8 of Fig. 4;

Fig. 9 is a fragmentary sectional view on the line 9 9 of Figs. 3 and 4;

Fig. 10 is a sectional view on the line it-l of Fig. 4;

Fig. 11 is a sectional view cn the llne lI-il of Fig. 2;

winding P and a single loop secondary Winding S I3-l3 and A Z connected with welding electrodes E, by suitable bus bars Bv (Figs. 1 and 2).

Referring to Figs. 3 and 4, shelf 22 supports brackets 341.! and 3DR which supports cylinder 3 IL and 3 IR, whose pistons are connected respectively with rods 32L and 32E which are pivotally connected with bars 33L and SSR respectively. Links 34L and 34B connect bars 32L and 35B. respectively with pairs of slides 35L and 35R respectively which are guided obliquely for movement to the horizontal (as viewed in Figs. 3 and 4) by pairs of rails 36L and 3lL, and 3ER and 37B, respectively. Slides StL and 36L respectively support copper electrode blocks SSL and 3ER, each connected with copper bus bar B, said blocks bein-g insulated from the slides by plates 39 and 4t, as shown in Fig. 8. Blocks 3L and 3BR, respectively support electrodes EL and ER. The connected bars B are capable of exing so as to allow horizontal movement of the blocks SZIL and 3BR.

The construction of the electrodes is the same. As shown in Fig. 8, the electrodes ER have a bore 4I, which receives a water inlet tube 42 passing through a bushing 43 in a sleeve 44 having a stem 45. Sleeve 44 rits within a bushing 46 which fits within a bore 41 in block 3ER. The bore 41 is closed by a stuiiing box receiving packing retained by a threaded plug 5B. The ducts through the tube 4'2 are connected to side passages 5| which lead into that portion of bore 4l between the sleeve 44 and the stuiing box 43, said portion being connected with a duct in block 3BR connected with a water source by a hose 52. A return hose 53 (Fig. 4) is connected with a duct in block 38B which is connected with holes 54 of sleeve 44 which communicate with the bore 4l in the electrode. Thus means are provided for the circulation of water into and out from the electrode.

Referring to Figs. 410, 12, 13 and 14, the table 22 supports a block 6l] located by dowels 6l and secured by screws E2 and havin-g a passage G3 through which water circulates. Block 6i] supports a copper wedge block 64 having slots G5 through which screws B5 extend thereby guiding the block for movement of adjustment in a horizontal direction as viewed in Fig. 12. From the position shown in Fig. l2, the block E4' can be moved to the right by turning a screw 61 which is secured in the desired position by lock nut 68. Then the screws 66 are tightened upon the block 60. Block 6i! supports guide block l' attached to block by locating dowels 1| and screws 12. Between the block 'it and the wedge 3 block Sii there are located two .dogs 73, each pivotally supported on a rod 'is carried by a block 76. Each dog has a tooth or point '|35 for engaging a tang it2t (Figs. 9 and 10) provided by a side plate |62 of the magnet core of the horn. The dogs 73 are urged clockwise by springs 'i6 received by holes 77 in block 60 and retainedv by plugs 78.

. Referring to Fig. 9, each screw 72 has a Stem 79 which terminates in a pad B upon which the horn base IE5@ rests. By turning the screw 'I2 the elevation of pad Se can be ladjusted 'andthe s-crew 'i2 is secured in the desired position by a lock nut 72a. As shown in Fig. vE), the `horn is placed in the welding machine with its base resting on the pads St at one side and withits base resting, as shown in Fig. 10, upon a wedgefa .on the other side. The horn has in effect a three point support.

The wedge t@ (Figs. l and 12) is supported -by a `copper bloclc guided for horizontal movement as viewed in Fig. '12'by ways or' rails "86 attached to a plate l87 (Fig. l0) by dowels-ili! and screws'i which also serve to secure the plate 87 to the table 22. The block carries blocks' 9i! located by dowels Si and screws 92 serveto attach the blocks Sii to the blocks 65. Between the edge-Sii andthe blocks 9d there are located dogs '93 which are-similar to the dogs 73 previously described. Dogs 93 are supported -by pins Vfirsupported bythe blocks. Dogs-Mare urged toward the tangs |2t by springs "d passing through holes'i 'in block/'85 and into `recesses SS provided by a block which issupported by the platei and is -guide'd by the rails By means to be-described, the block JSS is moved horizontaliy toward theleit as viewedin Fig. l2 in order to locate the wedge S@ firmly between the base tangs litand to force the Icore vassembly toward the wedge 6a. Motion is transmitted from-the block 99 to the block S5 by springs Ii located in vrecesses`l| provided by plate 85 and--recesses-||32 provided by block', Wedge Sli can be adjusted relative to block by turningra screw |55 4passing loosely through a hole in block 99 and threaded into block 35 so as to engage the wedge dit. The wedge #3@ is'guided `during this Yadjustment by screws |65 passing through slots '|97 -i-nthewedge and threaded'into'blockt. When the Wedge has been adjustedthe screwsY I' are tightened.

Theiplate99 -and'hence plate-85 are moved horizontally as .Viewed in Fig. i2 by a pneumatic servo-motor comprising a'cy-iinder It@ supported by a bracket II I,suppo1'ted 4by tablet?. The piston in cylinder I is Aconnected" by rodll i2 wit-ha pivot pin' I i3 carried by a slide I IS guided' by ways or rails H5 and I'it supported 'bythe plate '87 which, like the table '22, is provided withA an aperture through which the slide i I i extends. Upward motion of the slide I IG is limited by a screw |I7 threaded through abar I i8 "attac-hed to the 'rails I5 andIiG and secured inthe desiredposition of adjustment by 'nut IIS. The slide lift-has `an oblique cam slot I2@ which receives a roller |21 which a pin I22 pivotally connects with a bar l|23 ofthe lT formation, said bar 'being attached to block 99'by screws IM. Screws l'anddowels |26 Asecure the -parts H5 and IIS'tothe plate'S'I which in turn is'securcd Vby screws I2? tothe tab1e'22. When the slide I'Ili movesv up in Fig. 5, the bar |23 moves left and motion is transmitted by springs Iii to cause block''to move left. When the slide I t moves down the bar |23 moves right thereby causing the block 99 toy move right `and to engage the heads |30 of screws I3i which pass through holes |32 in block 99 and are threaded in the block 85. Thus the wedge Sli is positively retracted from the magnet core of the horn. During its Vertical movement slide i is operates a switch SW3 Whose plunger |35 is engaged by leaf spring |38 pivotally supporting a roller |37 enn gageable with a cam bar |38 attached to the slide lili, as shown in Fig. 6.

Figs. 9 and 10 show the horn H in position. The horn H comprises an assembly of projector -shells ld and I'l, a diaphragm |52, a gasket |53 andv abase |53. The diaphragm which is welded at its edges to the base |55, is connected by a rod |55 (Fig. 10) with an armature |56 and an armature spring |57, which together with a stack of circuit breaker part terminals and mulators is attachedY to a shelf |58 supported by the base |551 (Fig. 9). The rod|55 extends through the magnet core Il comprising @shaped laminations which receive a coil IGI. These laminations are bound together 'by side piates idg secured by rivetsl' passing through the .laminations An air-gap spacer `or shim, not shown, of predetermined thickness is placed 'between armature IEB and the pole pieces iiji `and '|653 'of magnet core. The coil ttl is connected with a current source, wires'from-which are connected respectively with two-resilientingers IE7 (Fig. 9) .one of which is secured to an insulating blocki-t supported by the table 22. Eachof these ngers E67 engages a plate IES with which wiresare ccnnected leadingto the coil ISI.

The horn H is located vas shown iniFigs 9 and l0 with its ,base ISI@ resting on the pads SQ and on the wedge 8. The wedges dil and 35i are located between pairs ofbase tangs Ift. The points 'I5 and 95 ofthe dogs 73 .and d3 engage the ends of the tangs It provided r.by the core side plates H32. "The frame is maintained 'this position byfa pad |76 pivotally `attached to a rod I'Il which, as shown in Fig. 2,'is pivotally connected with 'alever U72 which, Aas shown in Fig. 11, is connected with a rod |173 pivotally supported by a bracket-llt attached to the angle posts-23. Bracket |74 supports an air cylinder |75 whose piston is connected with a rod l Whosefhead isprovided with a slotil for receiving a pin Ilt passing through bar |72. By admitting compressed air tothe upper Vend oi cylinder |75, rod I 76 moves down .and .the rod |72 moves down to cause paid .176 .to press against the horn to maintain it in the `position shown. The magnet coil EBI is then energized tofcause theishim to -be tightly engaged by the armature |56 and the magnet core |50. Ccmpressed air is then admitted tothe `lower end of the cylinder IIB to cause thelwedge SI5 (-Fig. l0) to-move toward'the wedge B 4therebycausing the horn base tangs ldt to be tightly engaged by the wedges and causing the dogs 73. and 93 to press more tightly against the magnet core tangs ISt. The function of these dogs is to restrain vertical movement of tangs IiZt. Compressed a-ir is admitted to the leftAe-nd oi c'ylinder SI-L and to the vright end of cylinder 3|-R in order to cause the electrodes EL Vto move right and Velectrodes ERto rnoveleft in order to urge the tanges dtof the magnet coreassem-bly againstthe tangs v Iit o1" the horn base |511. Whiietree bars/SS-L and Edi-#R provide 'rior' equalization of pressure. Each of the tangs I62t hasa spherical projection S which lat -rstengages a tang |5575 causing the welding `current to be concentrated in a small area whereby'the temperature ef the projection S is quickly raised by the Vwelding current. As this projection S melts down the electrodes move in to force the tangs 162i -against the tangs |54t thereby completingthe assembly of the horn base and the horn magnet core while the gap between the horn armature and the pole faces is accurately maintained under pressure exerted magnetically between the armature and the pole faces.

There are two welding circuits. One includes the secondary of one of the welding transformers, the electrodes EL and ER which are upper as viewed in Figs. 3 and 4 and the tangs and the wedge 84 between them. The other includes the secondary of the other welding transformer, the electrodes EL and ER, which are lower as viewed in Figs. 3 and l and the tangs and the wedge B4 between them.

Fig. 15 is a hydraulic diagram showing the connections between various air cylinders and their control valves and the latter with a pipe |33 connected with a compressed air source. Pipe lili] is connected with the valve V2 which controls the ow of compressed air to the ends of cylinders 3|-L and 3l-R, with a valve Vl which controls the flow of compressed air to the cylinder ||ll and with a valve V3 which controls the ow of compressed air to the cylinder |15. These valves are located in boxes |8| and 182 supported by shelves |83 and |84, respectively supported by the posts 2|. The connections between valve V2 and the remote ends of cylinders 3|-L and 3|-R are provided by hose |85 and branch hoses |86 and |81. Valve V2 is connected with the adjacent ends of these cylinders by a hose |68 connected with branch hoses |89 and |50. Cylinder ||0 is connected with its valve V| by hoses |91 and |92. As shown diagrammatically in Fig. 15, the cylinder |15 is connected with its control valve V3 by pipes |93 and |94.

The box |95 which is supported by posts 23, houses electrical control apparatus which will now be described with reference to Fig. 16.

A switch SWE, when closed, connects a 220 volt A. C. source with ignitrons C| and C2 and flow switches FS. Ignitrons C| and C2 control the flow of current to the primaries P of the welding transformers T3 and T4. Switch SWI, when closed, connects switch SWB with the primary of a transformer Tl connected with one pole of switch SWI by normally open contacts Rlc of a relay having a magnet coil Rl. The secondary of transformer T| is connected with the horn magnet coil IBI by the members |61 (Fig. 9).

A switch SW2, when closed, connects switch SW with the primary of a transformer T2 whose secondary is connected with wires and |2. PBl is a normally open starting switch. FB2 is a normally closed stopping switch. S3 is the magnet coil which, when energized, causes the valve V3 to operate to cause the clamp pad |10 to engage the horn. R| is the magnet coil of a relay having normally open pairs of contacts R|C and R|C. SW3 is the switch which is closed when the piston rod ||2 (Fig. 6) rises. R2 is the magnet coil of a relay having normally open pairs of contacts R2C and RZC. TD2 is a vacuum tube time delay relay, for example one known to the trade as CR'1504-A1D having the terminal indicated with the dot-dash rectangle marked TD2. SI is the magnet coil which, when energized, causes yvalve Vl to operate to cause the wedge 84 to move toward the Wedge 64. R4 is the magnet coil of a relay hay ing normally open contacts R4C. S2 is the mag-l net coll which, when energized, causes valve V2 to operate to cause the electrodes EL and ER to move against the work. TDI is the magnet coil of a magnetic time delay relay having normally open contacts TDIc. R3 is the magnet coil of a relay having normally open pairs of contacts R3c which respectively control TD3 and TD4. TD3 is a NEMA-1A welding sequence timer having terminals indicated with the dotdash rectangle which represents this timer. TD3 controls the closing of normally open contacts BTO, the closing of which causes energization of magnet coil R5 of a relay having normally closed contacts R50. Switch SW4 connects TD3 with C|C which is an ignition contactor which controls ignitron C|. TD4 is a NEMA- 1A welding timer having the terminals indicated within the dot-dash rectangle which represents it. TD4 is connected by switch SW5 with C2G which is an ignitron contactor which controls ignitron C2.

The sequence of operations is as follows. The horn to be welded is mounted in the machine as described with the gap determining spacer or shim between its armature and magnet pole faces. Power is applied by closing switches SW6, SW| and SW2. Switch PBI is momentarily closed. Coil RI is energized and closes contacts R|C which causes current to flow to horn magnet coil IBI, thereby holding the spacer between the armature and magnet core by magnetic attracs tion. Coil S3 is energized to cause the clamp pad |10 to engage the horn. The other contacts RIC close to by-pass switch PBl so that Rl remains energized after PBl opens. TD2 starts timing. When TD2 times out, magnet coil S| is energized and the piston rod l2 (Fig. 6) moves up and switch SW3 closes and tne wedge 84 moves in and forces itself between the adjacent frame tangs |54t and the frame tangs |5415 remote therefrom against the wedge 64.

When SW3 closes, coil R2 is energized and contacts R20 and R20 close. R2c maintains energization of coil R2. Energization of R4 and S2 is effected by closing of RC2. S2 then causes valve V2 to operate to cause the electrodes EL and ER to move in against the work. R4 causes contacts R40 to close to energize TDI which after a certain time (the duration of which is called squeeze time) closes contacts TDlC which energizes relay coil R3 which closes contacts R30 and R3c which cause TD3 and TD4 to operate, TD3 operates through C|C to cause ignitrons Cl to pass current to the primary of transformer T3. TD4 operates through C2G to cause ignitrons C2 to pass current to the primary of transformer T4.

TD4 times out and stops current through C2. The weld control section of TD3 times out and stops current through C I. Welding current ceases while the electrodes are still forced against the work. After the lapse of hold time, the hold section of TD3 times out and contacts 5T() are caused to close. Relay coil R5 is energized and normally closed contacts R50 open. Coil Rl is deenergized and Rlc opens to disconnect the horn magnet coil |6|, and Ric opens to disconnect coil R2. Coil R2 is deenergized and contacts R20 and R20' open. Coil R4 is deenergized and contacts R40 open. TDI is deenergized and contacts TD lc open. Coil R3 is deenergized and contacts R3c and R30 open. The circuit is reset or restored to normal condition for another cycle which' is :initiated by momentarily closing switch PBI. t v t Y vThe cyclecan be ,stopped 4at anytime :byopening switch PE2. j

While :the embodiment ,of the present invention as herein disclosed, constitutes Va preferred form, it is to be understood that other forms might Vbe adopted, all coming within the scope-of the claims which follow.

What is claimedis as lfollows: y

1. Apparatus for. welding an electrcmagnet fassemblyrincludin-g a'coil and a core hav-ing pairs-of spaced .tangs .at opposite lends thereof to a `base having 'pairs of spaced tangs on opposite sides of za central region comprising, means for supl :porting Athe base and the core loosely assembled therewith :with the core .tangs straddlin-g `the .base tangs; ftwo wedges :each adapted -to occupy .the space between one pair of base tangs; means for energizing the coil to clamp an air-gap spacer between the core and an armature sup- ;.ported `by the base; means for eiecting relative movement between the wedges in a ,direction to cause :the ibase tangs `to :be engaged tightly =by the wedges.; yelectrodes engaging the vcore tangs; means :for forcing Lthe electrodes against the core tangs tand the latter against the base tangs; and means for supplying electric vcurrent to the :electrodes to elect a weld between the'tangs.

.2. Apparatus according to claim 1 having means Afor clamping the base assembly -u-pon fthe base supporting means.

3. Apparatus `according to ,claim 1 having means for restraining movementoi the core frelative to the base while the V coil isy energized and the electrodes vare caused to move against the core tangs.

:4. ,Apparatus according to claim 1 having dogs pivotally supported by the wedges and .each havingk a tooth for engaging the end of a core tang for restraining movement of the core relative tothe base while the coil is energizedand the electrodes are caused to move against the core tangs.

5. Apparatus according to claim 1 in which the support for the base comprises one of y.the wedges and two pads located adjacent opposite sides of the other wedge. 1

6. Apparatus .according to claim v1 in which the coil fis connected with terminal members which respectively engage spring conductors when the base is placed on the support, and .the energization of the coil is effected ,by-connecting the spring conductors with `a current source.

V'7. Apparatus according to claim 1 in which the four vcore tangs are forced :respectively by four electrodes respectively against four base tangs which respectively contact the four side surfaces of the two wedges and electric current is applied to the electrodes by `the prov-isimi of two welding transformers each having a primary coil connected with a current source and a :Secondary winding in series with electrodes on fopposite sides of a wedge, ,a wedge and the lcore and base tangs located between the electrodes and wedge.

8. Apparatus according to `claim 1 in which the four electrodes are arranged in v'two pairs ,on vvopposite sides of the wedges and each pair is moved by a common operating member -niechanically connected with the electrodes of the pair 4.by means which will 'equalize the pressures applied by the electrodes. l

9. Apparatus for welding an electromagnet assembly including a coil and afcore having pairs 8 of spaced tangs at opposite ends thereof to a basehaving pairs of spaced tangs on opposite sides of a central region; means for supporting the 'base and the core loosely assembled therewith with the sore tangs straddling the base tangs; a stationary wedge adapted to occupy the space between one pair of kbase tangs; a movable wedge adapted to occupy the space between the other pair of base tangs; means for energizing the coil to clamp an air-gap spacer between the core and an armature supported by the base; means for actuating the movable wedge in a direction to cause the base tangs to be engaged tightly by the wedges; electrodes engaging the core tangs; means for forcing the electrodes against the core tangs and the latter against the base tangs; and means for'supplying electric current to the electrodes to effect a weld between the tangs.

10. Apparatus for welding an electromagnet assembly including :a coil and core having pairs of spaced tangs provided with spherical projections ,at lopposite ends thereof to a base having pairs of spaced tangs on opposite sides of a central region; means for supporting the base and the core loosely assembled therewith with the core tang projections straddling the base tangs; a stationary wedge to occupy space between one pair of base tangs; a movable wedge adapted to occupy the space between the other pair of base tangs; means for engaging the coil to clamp an air spacer between the core and an armature supported by the base; means vfor actuating the movable wedge in a directionto cause the base tangs v-to `be engaged rrnly by the wedges; electrodes engaging the core tangs; means forcing the electrodes against the core tangs until the projections engage the base tangs; and means for applying electric current to the electrodes causing the Aprojections 'to melt and to eect a weld between the tangs.

11. Apparatus for welding an electromagnet assembly including a coil and core having pairs of spaced tangs provided with spherical projections .at oppositeends thereof to a base having pairs of spaced tangs provided with spherical projections on'opposite sides of a central region; means for supporting `the base and the core loosely assembled therewith with the projections of the core tangsv straddling the projections of the base tangs; a stationary lwedge adapted to occupy the space between one pair of base tangs; a movable wedge adapted to occupy the space between the other Apair of base tangs; means for energizing the coil to clamp an air gap spacer between the core and an armature supported by the base; means for actuating the movable wedge in a direction to cause the base tangs to be engaged tightly by the wedges; .electrodes engaging the core tangs; means for forcing ythe electrodes against the core tangs until the projections therein make point contact engagement with the projections of the base tangs; fand means for supplying electric vcurrent to the'electrodes to fuse the projections.

y12. Apparatus for use in welding an electromagnet assembly including a coil and a core having pairs of spaced tangs at opposite ends thereof to Ia base Vhaving pairs of spaced tangs on opposite sides of a-central region comprising, a support for the base with-the core loosely mounted on the base, a plurality of wedges adapted to abut the base tangs; means for moving one of the wedges so that all of the wedges will be in abutting relation with respect to base tangs; means for engaging the coil to clamp an element between the core and an armature supported by the base to provide the correct air gap therebetween; a plurality of electrodes adapted to engage the core tangs; means for forcing the electrodes against the core tangs so as to clamp the core and base tangs between the electrodes and the wedges; means for connecting the electrodes with a current source to weld the core tangs to the base tangs; and a system of control for effecting the operations of said means in timed relation.

'13. Apparatus for use in welding an electromagnet assembly including a coil and a core having pairs of spaced tangs at opposite ends thereof to a base having pairs of spaced tangs on opposite sides of a central region comprising, means for supporting the base and the core loosely assembled therewith with core tangs adjacent base tangs; a plurality of wedges adapted to abut the base tangs; means for moving at least one of the wedges whereby all of the wedges will be in abutting relation with respect to the base tangs; means for clamping the base upon the supportin g means; means for effecting the energization of the electromagnet coil to clamp an air gap spacer between the core and an armature supported by the base; a plurality of electrodes adjacent the core tangs; means for advancing the electrodes against the core tangs and the latter against the base tangs; means for connecting the electrodes with a current source to effect a weld between the core tangs and base tangs; and a system of control for eiecting the operation of all said means in timed relation.

14. Apparatus for welding an electromagnet assembly including a coil and a core having tangs to a base having tangs comprising, means for supporting the base and the core loosely assembled therewith with core tangs adjacent base tangs;

10 members adapted to engage the base tangs; means for energizing the coil to clamp an element between the core and an armature supported by the base to assure a space between the core and armature; means for effecting relative movement between the members so that the members will be in abutting positions with respect to the base tangs; electrodes engaging the core tangs; means for forcing the electrodes against the core tangs, and the latter in abutment with the base tangs; and means for supplying electric current to the electrodes to effect a weld between the tangs.

15. Apparatus for welding an electromagnet assembly including a coil and a core having tangs to a base having tangs comprising, means for supporting the base and the core loosely assembled therewith with core tangs adjacent base tangs; members adapted to engage the base tangs; means for energizing the coil to clamp an element between the core and an armature supported by the base to assure a space between the core and armature; electrodes engaging the core tangs; means for moving the electrodes to clamp the core tangs and the base tangs between the electrode and members; and means for supplying electric current to the electrodes to effect a weld between the tangs.

JOHN R. WIRT. WAYNE H. SHELEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,995,759 Strickland Mar. 26, 1935 2,006,459 Jones et al July 2, 1935 

